The USGS has a new "experimental" water "dashboard" that's pretty cool. For rivers that I boat a lot, I downloaded an app for my phone called riverflows.net that queries the USGS system. Very easy to use and in real time.
Access water information and weather conditions in your neighborhood! A map viewer showing real-time water data collected at U.S.Geological Survey observation stations in context with weather-related data from other public sources.
For Colorado; this site below has been helpful. Just literally zoom into the section you want, and click around on the available stations. Gives you some nice historical data that's easy to read. Updated on the hour pretty regularly.
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